SEOUL — The Pentagon’s top general arrived in South Korea’s capital Thursday, preparing to meet with senior South Korean military officials ahead of President Trump’s visit next month and amid a heightened threat of war with North Korea.

Marine Gen. Joseph F. Dunford Jr., the chairman of the Joint Chiefs, said that his annual meeting with senior South Korean military officials will address everything from bolstering ballistic missile defense to fortifying computer networks against cyber-espionage. Dunford called the meeting a “forcing function” that dates back to 1978 and keeps South Korean and U.S. military officials assessing each other’s priorities.

“We have been on a path toward increased South Korean capability for a long time,” Dunford said. “And so, the more that they can do for themselves, clearly the better, and the more effective the deterrence is” against North Korea.

Dunford, speaking on a military aircraft traveling from Washington, said that he will discuss a South Korean request for ballistic missiles with larger conventional warheads and other upgrades to the South Korean military’s ground and maritime weapons. Another discussion will focus on upgrading South Korean military networks for the sake of commanding and controlling U.S. and South Korean troops.

The meeting comes during a year in which rhetoric with North Korea has been supercharged. Trump has belittled North Korean leader Kim Jong Un as “Rocket Man,” and “Little Rocket Man” and suggested that “talking is not the answer” against Pyongyang. Kim, referring to Trump, has threatened to “tame the mentally deranged U.S. dotard with fire.”

Trump’s senior advisers have sought to underscore the decades-old alliance between South Korea and the United States and make it clear that diplomatic action led by Secretary of State Rex Tillerson is the preferred course of action. But military power underpins that strategy, and the Pentagon regularly has shown its collaboration with South Korea through actions such as flying armed bombers and fighters over South Korea. About 28,500 U.S. troops have been stationed there for years.

Defense Secretary Jim Mattis also is expected to visit defense officials in South Korea this week, picking up where Dunford leaves off. The chairman, meanwhile, will continue his conversations over the weekend in Hawaii. He is meeting in a three-party gathering there with his South Korean counterpart, Gen. Jeong Kyeong-doo, and their Japanese equivalent, Adm. Katsutoshi Kawano.

The meetings come after a South Korean announcement earlier this month that North Korean hackers stole a huge trove of South Korean military documents last year, including a plan to kill senior North Korean leaders in the event of a war.

Lee Cheol-hee, a member of the ruling Democratic Party and parliamentary national defense committee, said this month that the hackers broke took numerous secret files. They included OPLAN 5015, a plan drafted in case there was a full conflict with North Korea, and OPLAN 3100, which outlined the military response if North Korea’s robust Special Operations force infiltrated their neighbor to the south, the lawmaker said.

Dunford declined to identify who was behind the hacking, but said the incident is cyberespionage. Adversaries are “probing the lines in cyberspace every day” with allies and both Europe and Asia, he said. Without identifying what was taken, he said the incident is characteristic of the 21st century, but a permutation of old-school spy craft.

“It’s something that has gone on forever,” Dunford said. “In the old days, it was someone sneaking into a building under the cover of darkness and breaking into a file cabinet. And now, it’s someone trying to break into a system. But, it’s been going on since there has been war.”

South Korean officials also have inquired about reintroducing tactical nuclear weapons on the peninsula during an Aug. 30 visit to Washington, Mattis said last month. He declined to elaborate on the possibility. They were kept in South Korea throughout much of the Cold War, but were removed by President George H.W. Bush in 1991 after the fall of the Soviet Union.

The meetings this week come amid an unusual time frame in which the North Korean regime has not launched a test missile since Sept. 15 in South Korea. Dunford said that Kim’s schedule may be driven by technical considerations as North Korea prepares to launch them, his nation’s relations with China and an upcoming security meeting in Asia.

“I wouldn’t say I am surprised. I would say this is something we watch all the time in anticipation,” Dunford said of the lack of recent launches. “Most importantly, we just make sure we have our defensive systems in place.”

The Navy announced this week that it also has deployed three aircraft carriers — the USS Nimitz, the USS Theodore Roosevelt and the USS Ronald Reagan — and their associated strike groups to the western Pacific this week. The movement of the strike groups, each of which include dozens of strike aircraft and thousands of U.S. sailors and Marines, is often viewed as a show of force, but Dunford downplayed the timing.

“These three carriers are not there specifically targeting North Korea,” the chairman said. “This is a routine demonstration of our commitment to the region.”